Does Strong Stratification Affect our Ability to Remotely Sense Chlorophyll-a Concentration along Shelf Waters off Delmarva Region, VA?

Does Strong Stratification affect our ability to remotely sense chlorophyll-a concentration along shelf waters off Delmarva Region, VA?

Michael J. Burns and Ajoy Kumar

Department of Earth Sciences

Millersville University, PA

 

  Bi-weekly transects in 2005-2007 obtained from Coastal Ocean Buoy (COBY) cruises showed a clear seasonal progression of the water column, with strong stratification during summer followed by mixing during late fall, winter, and spring. In the shelf waters of the region, the summer patterns in the vertical stratification of the phytoplankton community parallel spatial patterns in physical density stratification. The subsurface phytoplankton maxima track the thermocline/pycnocline. Dense phytoplankton biomass found in the thermocline/pycnocline represents a potentially highly significant source of carbon/energy for herbivores. The water-leaving radiance detected by passive ocean color satellites such as VIIRS and MODIS is from just the upper 1/5^th of the productive euphotic layer (O’Reilly & Zetlin, 1998). Consequently, these strong subsurface chlorophyll maxima are not detected.  We have sampled the same COBY transect from 2008 to 2016. In this poster, we will illustrate how warm temperatures over the years have contributed to strengthening the stratification during summer and what consequences it may have for chlorophyll detection from satellites.